No need to fast before cholesterol test, major analysis
Patients do not need to
fast before doctors measure their cholesterol levels, a major new
analysis funded by the British Heart Foundation (BHF) confirmed
After analysing data on
over 300,000 people, researchers at the University of Cambridge
concluded that tests can be made simpler and more
convenient without making predictions less accurate.
Together, heart disease
and stroke are the leading cause of death worldwide. Doctors
currently use a combination of tests in a cardiovascular risk
assessment to assess a patient’s likelihood of having a heart
attack or stroke in the future. This includes blood tests for
cholesterol and other
circulating lipids, for which doctors may ask patients to go
without food for 12 hours beforehand.
By collating data from 68
long-term surveys in 21 countries, Professor John
Danesh and his collaborators have shown that blood tests
on non-fasted patients predict heart and circulatory disease risk
just as well as tests on fasted patients.
”For decades, people have
been asked to fast overnight before their cholesterol tests,”
Professor Danesh said. “These findings indicate that cholesterol
measurements are at least as good – and probably somewhat better –
when made without fasting.”
Professor Peter Weissberg, Medical
Director of the BHF, emphasised that doctors may still require
patients to fast for other tests.
“Some people may find
that even if your cholesterol test can be done at any time, your GP
may ask you to fast before your appointment so that he or she
can test accurately for diabetes. If you’re having an overall
health ‘MOT’, this will not be uncommon practice.”
The study also sought to
resolve controversy among experts over which blood tests best
assess a person’s risk of heart attacks and strokes. Some experts
have advocated that tests for blood proteins called apolipoproteins
should replace the more common tests for cholesterol. As well as
these tests, some doctors may also measure blood concentrations of
triglycerides, a type of fat molecule.
The results show that
measuring total cholesterol and HDL or ’good‘ cholesterol is just
as informative as testing for apolipoproteins AI and B. The study
also found that triglyceride measurements do not provide any extra
information about heart disease risk on top of the other tests.
The findings, published
in the Journal of the American Medical Association (JAMA), should
influence new cardiovascular guidelines that are being drawn up for
doctors in the UK, US and Europe.
“Given the financial
pressure the NHS is under, it’s good news that
doctors don’t need to spend money on setting up more sophisticated
tests based on apolipoproteins," Professor Weissberg added. "But
the study underlines the importance of all GPs being able
to measure HDL cholesterol as well as total cholesterol,
in order to make the best predictions about heart disease